The present invention relates to an active energy ray-curable urethane (meth)acrylate and an active energy ray-curable composition.
As conventional coating agents and paints having abrasion resistance, ultraviolet curable hard coating agents, electron beam-curable hard coating agents, silica-type hard coating agents, and two-pack type acrylurethane soft paints are known. As conventional paints and coating agents having lubricity, those obtainable by crosslinking polydimethylsiloxane graft compounds or block copolymers with an isocyanate or melamine are known.
However, in the conventional hard coating agents, crosslinking density of the hard coating agents is increased by employing a rigid monomer. The hard coating agents form coated films through curing but the coated films shrink during their curing to cause a relatively large strain. Therefore, the coated films derived from the conventional hard coating agents exhibit a low adhesiveness to a substrate and also chipping and cracks tend to occur in the coated films.
The conventional hard coating agents form hard and brittle coated films. Therefore, in light-diffusive sheets produced by applying the hard coating agents onto a substrate sheet made of a plastic, it becomes difficult to subject the light-diffusive sheets to secondary processing. Moreover, at the time when the conventional hard coating agents are applied onto a substrate sheet, the substrate sheets curl and hence cracks tend to occur at the resulting coated films.
On the other hand, in a conventional two-pack type acrylurethane soft paint, there occurs no problem such as chipping and cracks. However, the two-pack type acrylurethane soft paint exhibits poor workability because the period of time capable of applying the paint is limited and it takes a long time to cure it by drying. Furthermore, the coated film formed from the two-pack type acrylurethane soft paint is poor in solvent resistance and blocking resistance. When polydimethylsiloxane oil is added in order to improve blocking resistance, transparency of the coated film, adhesiveness to a substrate, and re-coating properties decrease.
In addition, the conventional paints and coating agents are very excellent in lubricity but it is impossible to re-coat a silk printing on coated films thereof.
An object of the present invention is to provide an active energy ray-curable urethane (meth)acrylate and active energy ray-curable composition which have an enhanced abrasion resistance and lubricity and are suitably usable as a paint or coating agent. Another object of the present invention is to provide uses of the urethane(meth)acrylate and the composition.
For achieving the above objects, in one embodiment of the present invention, provided is an active energy ray-curable urethane (meth)acrylate which has an alkyl group having 13 to 25 carbon atoms and an active energy ray-curable functional group and is modified with polycaprolactone.
The active energy ray-curable urethane (meth)acrylate is obtainable by reacting an organic isocyanate having three or more isocyanate groups in one molecule, an alkyl alcohol having 13 to 25 carbon atoms, and a polycaprolactone-modified hydroxyethyl (meth)acrylate.
It is preferred that the molar ratio of the isocyanate group of the organic isocyanate, the hydroxyl group of the polycaprolactone-modified hydroxyethyl (meth)acrylate, and the hydroxyl group of the alkyl alcohol is 1:0.8 to 1.20:0.02 to 0.33.
In another embodiment of the present invention, an active energy-ray curable composition is provided. The composition comprises an active energy ray-curable urethane (meth)acrylate with an alkyl group having 13 to 25 carbon atoms and an active energy ray-curable functional group and is modified with polycaprolactone, and at least one selected from a compound having an active energy ray-curable functional group copolymerizable with the urethane (meth)acrylate, organic beads, inorganic beads, and an antistatic agent.
The other embodiments and advantages of the present invention may become apparent from the following description along with the drawings illustrating the examples of principle of the present invention.